1994 buick roadmasters stall when it warms up replaced pcm mafs ingnition module coil cap rotor idle control valve plugs wires will run fine then sputters and eventually stalls they tell me the catalitic converters look fairly new have not changed o2 sensors yet have a check engine light on

You need to retrieve the codes using an OB11 meter. It could be a number of things causing your problem. It could be an o2 sensor, coolant sensor, idle sensor or the fuel filter . I doubt it's the converter. OB11 is not too expensive & easily read. They range in price from 40-200 dollars. The cheaper one will suffice. Good luck! PS I don't think OB11 will read on your car; however, check with any autoshop & they may be able to show you the proper tool to obtain the codes. Good luck!